If you are aspiring to be a hacker or a Unix/Linux guru, then you have probably read some of Eric S. Raymond's writings like 'The New Hacker's Dictionary' and 'The Art of Unix Programming'. You may have also visited his website and read some of his articles there.

If you haven’t been to ESR’s site, there are interesting pages there that contain some ‘koans’.

From Wikipedia:

A kōan (公案; Chinese: gōng-àn, Korean: gong'an, Vietnamese: công án) is a story, dialogue, question, or statement in the history and lore of Chán (Zen) Buddhism, generally containing aspects that are inaccessible to rational understanding, yet may be accessible to intuition. A famous kōan is: "Two hands clap and there is a sound; what is the sound of one hand?"

Raymond’s own version of koans entitled, ‘The Unix Koans of Master Foo’ is filled with humor and wisdom that every wannabe hacker should enjoy. Here are a couple of Unix koans that I took from ESR’s website:

Master Foo and the Unix Zealot

A Unix zealot, having heard that Master Foo was wise in the Great Way, came to him for instruction. Master Foo said to him:

“When the Patriarch Thompson invented Unix, he did not understand it. Then he gained in understanding, and no longer invented it.”

“When the Patriarch McIlroy invented the pipe, he knew that it would transform software, but did not know that it would transform mind.”

“There is a path,” said Master Foo, “that might bring you to wisdom.” The master scribbled an IP address on a piece of paper. “Cracking this box should pose you little difficulty, as its guardians are incompetent. Return and tell me what you find.”

The stranger bowed and left. Master Foo finished his meal.

Days passed, then months. The stranger was forgotten.

Years later, the stranger from the land of Woot returned.

“Damn you!” he said, “I cracked that box, and it was easy like you said. But I got busted by the FBI and thrown in jail.”

“Good,” said Master Foo. “You are ready for the next lesson.” He scribbled an IP address on another piece of paper and handed it to the stranger.

“Are you crazy?” the stranger yelled. “After what I've been through, I'm never going to break into a computer again!”